Melcher Tobias, Gruber Oliver
Department of Psychiatry, Systems Neuroscience Unit, Georg-August-University, Goettingen, Germany.
Cortex. 2009 Feb;45(2):189-200. doi: 10.1016/j.cortex.2007.06.004. Epub 2008 Jan 31.
In the current event-related functional magnetic resonance imaging (fMRI) study, we sought to trace back Stroop-interference to circumscribed properties of task-irrelevant word information - response-incompatibility, semantic incongruency and task-reference - that we conceive as conflict factors. Thereby, we particularly wanted to disentangle intermingled contributions of semantic conflict and response conflict to the overall Stroop-interference effect. To delineate neural substrates of single factors, we referred to the logics of cognitive subtraction and cognitive conjunction. Moreover, in a second step, we conducted correlation analyses to determine the relationship between neural activations and behavioral interference costs (i.e., conflict-related reaction time (RT) slowing) so as to further elucidate the functional role of the respective brain regions in conflict processing. Response-incompatibility was associated with activation in the left premotor cortex which can be interpreted as indicating motor competition or conflict, i.e., the presence of competing response tendencies. Accordingly, this activation was positively correlated with behavioral conflict costs. Semantic incongruency exhibited specific activation in the anterior cingulate cortex (ACC), the bilateral insula, and thalamus as well as in left somatosensory cortex. As supported by the consistent negative correlation with behavioral conflict costs, these activations most probably reflect strengthened control efforts to overcome interference and to ensure adequate task performance. Finally, task-reference elicited activation in the left temporo-polar cortex (TPC) and the right medial superior as well as in left rostroventral prefrontal cortex (rvPFC, sub-threshold activation). As strongly supported by prior studies' findings, this neural activation pattern may underlie residual semantic processing of the task-irrelevant word information.
在当前这项与事件相关的功能磁共振成像（fMRI）研究中，我们试图将斯特鲁普干扰追溯到任务无关单词信息的特定属性——反应不相容性、语义不一致性和任务关联性，我们将这些视为冲突因素。由此，我们特别想厘清语义冲突和反应冲突对整体斯特鲁普干扰效应的交织影响。为了描绘单个因素的神经基础，我们参考了认知减法和认知结合的逻辑。此外，在第二步中，我们进行了相关性分析，以确定神经激活与行为干扰成本（即与冲突相关的反应时间（RT）减慢）之间的关系，从而进一步阐明各个脑区在冲突处理中的功能作用。反应不相容性与左侧运动前皮层的激活相关，这可以解释为表明存在运动竞争或冲突，即存在相互竞争的反应倾向。因此，这种激活与行为冲突成本呈正相关。语义不一致性在前扣带回皮层（ACC）、双侧岛叶、丘脑以及左侧躯体感觉皮层表现出特定激活。这些激活与行为冲突成本始终呈负相关，这表明这些激活很可能反映了为克服干扰并确保任务表现适当而加强的控制努力。最后，任务关联性在左侧颞极皮层（TPC）、右侧内侧额叶上部以及左侧吻腹前额叶皮层（rvPFC，阈下激活）引发激活。正如先前研究结果所有力支持的那样，这种神经激活模式可能是任务无关单词信息残留语义处理的基础。
